This invention relates to an apparatus for automatically segregating, by weight, the various components of an admixture of shredded metalic and non-metalic materials at the end of a shredding and reclamation process for discarded scrap, such as automobiles, refrigerators and the like. It also relates to an apparatus capable of directly mechanically separating out shredded components of a mixture, by weight, without recourse to expensive flotation systems, cyclone separators or the like. The apparatus utilizes pneumatic suction, selectively variable in degree, to attract admixture components to the surface of a rotating drum which, in turn, deposits such components, in accordance with the weight thereof, onto various conveyor belts for transmission to points of utilization.
A fast and economical approach to reclaiming nonferrous metals, in shredded form, from an admixture of lint, rubber, glass and other debris at the end of a scrap process has eluded industry for some time. The problem has been particularly vexing for small scale scrap operations without the finances or space for the elaborate and expensive separation systems now known to the art. Some of these systems include flotation chambers, causing scrap to pass through liquid pools of various specific gravities, trommels, hugh cyclone separators, bagging rooms, etc. In the past, most small operations either had to send their resultant scrap out for processing in gross, non-separated condition, or had to utilize a plurality of workers to separate out a substantial portion of the valuable nonferrous "red metals" such as cooper, brass and other materials, manually.
In the typical large volume auto scrap or solid waste management operation, the principal object is to recover valuable metals for recycling. Scrap in the form of automobiles, refrigerators, and other appliances are crushed and then fed to a shredding machine from whence a shredded admixture is conveyed to some form of air separator where a part of the light combustible materials may be burned off. Glass and certain other materials are removed by means of a trommel or shaker device. The resultant shredded admixture is composed of iron, steel, nonferrous metals, and mixed organic and inorganic wastes. This mixture is sent to a magnetic separator which removes the ferrous metals.
Most modern installations utilize a wet, or flotation separating system for removing the organic and inorganic waste such as rubber, plastic, fabric, fiber and dirt, from the admixture prior to the magnetic separation of ferrous from nonferrous metals. Such wet processing systems are typified by the WEMCO RC Separator, manufactured by the Envirotech Corporation of Sacramento, CA. "WEMCO" is a trademark of Envirotech Corporation. The alternative to wet processing of the admixture prior to separation of ferrous from nonferrous metals is the objectionable production of fumes, smoke, dust and odors generated by the friction and heat caused by dry shredding and separating.
The present invention, in one embodiment, is capable of efficiently and cleanly separating out the components of an admixture either prior to or subsequently to the removal of ferrous metals by magnetic means. The present system performs without an objectionable level of dust and odor production and without recourse to liquid current or flotation means. The present system operates by direct mechanical contact with the components of the scrap admixture and attracts out components thereof by weight through the simple expedient of air pressure.
The use of air suction systems of various types, per se, have been known in the agricultural industry for some time. For example, U.S. Pat. Nos. 2,783,888; 1,485,401; 3,961,397; and 3,815,178 to Dahlstrom et al.; McDonough, et al.; Neuenschwander; and Goldman, respectively, teach the use of suction in processing cotton, tobacco and the like. However, to this point, no one has applied the beneficial principles utilized in agricultural processing to large scale heavy-duty reclamation of metals and other heavy particulate from auto scrap and solid waste operations nor has the specific apparatus for applying such principles been devised.
The present invention engrosses the application of negative air pressure to rotary drum means and includes means for varying such air pressure for the purpose of automatically separating out and conveying metals having different weights or densities.